CN114375392A - Diagnosis of cause of deterioration of lithium secondary battery - Google Patents

Diagnosis of cause of deterioration of lithium secondary battery Download PDF

Info

Publication number
CN114375392A
CN114375392A CN202180005251.7A CN202180005251A CN114375392A CN 114375392 A CN114375392 A CN 114375392A CN 202180005251 A CN202180005251 A CN 202180005251A CN 114375392 A CN114375392 A CN 114375392A
Authority
CN
China
Prior art keywords
lithium
secondary battery
positive electrode
pattern
active material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202180005251.7A
Other languages
Chinese (zh)
Other versions
CN114375392B (en
Inventor
尹孝贞
李恩周
金素英
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LG Energy Solution Ltd
Original Assignee
LG Energy Solution Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by LG Energy Solution Ltd filed Critical LG Energy Solution Ltd
Publication of CN114375392A publication Critical patent/CN114375392A/en
Application granted granted Critical
Publication of CN114375392B publication Critical patent/CN114375392B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
    • G01N23/207—Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
    • G01N23/2055—Analysing diffraction patterns
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4285—Testing apparatus
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/05—Investigating materials by wave or particle radiation by diffraction, scatter or reflection
    • G01N2223/056—Investigating materials by wave or particle radiation by diffraction, scatter or reflection diffraction
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/60—Specific applications or type of materials
    • G01N2223/606—Specific applications or type of materials texture
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/60—Specific applications or type of materials
    • G01N2223/611—Specific applications or type of materials patterned objects; electronic devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/60—Specific applications or type of materials
    • G01N2223/632—Specific applications or type of materials residual life, life expectancy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Pathology (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Molecular Biology (AREA)
  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Materials Engineering (AREA)

Abstract

The present invention provides a nondestructive diagnosis method capable of diagnosing deterioration of a lithium secondary battery without disassembling the battery, and provides a method of diagnosing a cause of deterioration of the lithium secondary battery, the method including: (A) manufacturing a lithium secondary battery including a cathode and an anode, the cathode including a layered cathode active material; (B) obtaining a first pattern showing a change in a c-axis d-spacing value of the layered positive electrode active material according to a number of moles of lithium ions deintercalated from the layered positive electrode active material during charging, from X-ray diffraction (XRD) data obtained during first charging of the lithium secondary battery; (C) obtaining a second pattern showing a change in a c-axis d-spacing value of the layered positive electrode active material according to a number of moles of lithium ions deintercalated from the layered positive electrode active material during charging, from XRD data obtained during second charging of the lithium secondary battery; and (D) classifying the cause of deterioration of the lithium secondary battery by comparing the first pattern and the second pattern.

Description

Diagnosis of cause of deterioration of lithium secondary battery
Technical Field
Cross Reference to Related Applications
The present application claims priority and benefit of korean patent application No. 10-2020-0063393, filed on 27/5/2020, the disclosure of which is incorporated herein by reference in its entirety.
Technical Field
The present invention relates to a method of diagnosing a cause of deterioration of a lithium secondary battery. In particular, the present invention relates to a method for diagnosing the cause of deterioration of a lithium secondary battery in a non-destructive manner using X-ray diffraction (XRD) data measured without disassembling the battery.
Background
Due to the development of technology and the increase in demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing. Among these secondary batteries, lithium secondary batteries having high energy density and high voltage, long cycle life and low self-discharge rate have been commercialized and widely used. In particular, with the rapid spread of electric vehicles in recent years, the development of high-energy batteries that can be used as power sources for medium-and large-sized devices has become increasingly important.
Lithium transition metal composite oxides have been used as positive electrode active materials for the above-mentioned lithium secondary batteries, among which lithium transition metal composite oxides having a high storage capacity are mainly usedLithium-cobalt composite metal oxides with high operating voltage and excellent capacity characteristics, e.g. LiCoO2. However, LiCoO2Has an unstable crystal structure due to the deintercalation of lithium, and thus has very poor thermal properties. In addition, due to LiCoO2It is expensive, and thus has a limitation in its use as a power source in a large amount in fields such as electric vehicles.
As LiCoO2As an alternative to (2), lithium manganese complex metal oxides (LiMnO) were developed2、LiMn2O4Etc.), lithium iron phosphate compounds (LiFePO)4Etc.) or lithium nickel composite metal oxide (LiNiO)2Etc.). Among them, research work on lithium nickel composite metal oxides is particularly active, and a large capacity battery can be easily realized due to its high reversible capacity of about 200 mAh/g. However, with LiCoO2In contrast, LiNiO2There are problems such as low thermal stability, and when an internal short circuit occurs in a charged state due to pressure or the like applied from the outside or the like, the positive electrode active material itself is decomposed, causing the battery to crack and catch fire. Therefore, LiNiO is maintained as a substance2As a method for improving low thermal stability while having excellent reversible capacity, a lithium transition metal oxide in which a part of nickel (Ni) is substituted with cobalt (Co), manganese (Mn) or aluminum (Al) has been developed.
However, in the case of the above-described lithium transition metal oxide in which a part of Ni is substituted by Co, Mn, or Al, when the Ni content is increased to 60 mol% or more to achieve high energy by improving capacity characteristics, there are problems in that lithium present in the positive electrode active material is deintercalated at a high potential and forms a new phase, and the structural stability of the positive electrode active material is deteriorated due to the phase transition, thereby causing deterioration of the battery.
Conventionally, in order to diagnose specific causes of battery deterioration, such as loss of usable lithium, loss of positive electrode capacity, loss of negative electrode capacity, and the like, it is necessary to disassemble the battery, and reassemble the positive and negative electrodes separated therefrom into half-cells, which are then analyzed to verify the cause. However, in this case, there are problems in that diagnosis of battery deterioration is time-consuming and expensive, and the disassembled battery cannot be reused.
Therefore, it is required to develop a method of diagnosing the cause of deterioration of a secondary battery, which is capable of classifying and quantifying the cause of deterioration of the battery without disassembling the secondary battery.
Disclosure of Invention
Technical problem
The present invention aims to provide a method of diagnosing the cause of deterioration of a lithium secondary battery in a nondestructive manner, which is capable of diagnosing the cause of deterioration without disassembling the battery.
Technical scheme
An aspect of the present invention provides a method of diagnosing a cause of deterioration of a lithium secondary battery, the method including: (A) manufacturing a lithium secondary battery including a cathode and an anode, the cathode including a layered cathode active material; (B) obtaining a first pattern showing a change in a c-axis d-spacing value of the layered positive electrode active material according to a number of moles of lithium ions deintercalated from the layered positive electrode active material during charging, from XRD data obtained during first charging of the lithium secondary battery; (C) obtaining a second pattern showing a change in a c-axis d-spacing value of the layered positive electrode active material according to a number of moles of lithium ions deintercalated from the layered positive electrode active material during charging, from XRD data obtained during second charging of the lithium secondary battery; and (D) classifying the cause of deterioration of the lithium secondary battery by comparing the first pattern and the second pattern.
Advantageous effects
According to the present invention, it is possible to classify and quantify the cause of deterioration of a secondary battery using XRD data measured without disassembling the battery.
According to the diagnostic method of the present invention, it is possible to determine whether the deterioration of the secondary battery is due to the loss of available lithium, the loss of the positive electrode capacity, or both the loss of available lithium and the loss of the positive electrode capacity, and quantify the loss of available lithium and the loss of the positive electrode capacity without disassembling the battery.
That is, the cause of deterioration of the lithium secondary battery can be diagnosed in a simple and nondestructive manner.
Drawings
Fig. 1 shows a graph illustrating charge potential distributions of a full cell and a positive-electrode half cell and a negative-electrode half cell manufactured using a positive electrode and a negative electrode obtained by disassembling the full cell, which are obtained to diagnose the cause of deterioration of a lithium secondary battery by a conventional method.
Fig. 2 shows a graph illustrating the change in the c-axis d-spacing value of the layered cathode active material of the secondary battery of example 1 according to the number of moles of lithium ions deintercalated from the layered cathode active material during the first charge or the second charge.
Detailed Description
Hereinafter, the present invention will be described in more detail to facilitate understanding of the present invention.
The terms and words used in the present specification and claims should not be construed as being limited to only general or dictionary meanings, but should be construed to have meanings and concepts consistent with the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of the term in order to describe his invention in the best way.
The terminology used in the description is for the purpose of describing the exemplary embodiments only and is not intended to be limiting of the invention. In this specification, the singular expressions include the plural expressions unless the context clearly dictates otherwise.
It will be understood that terms such as "comprising," "including," "having," and the like, when used in this specification, specify the presence of stated features, integers, steps, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof.
< method for diagnosing cause of deterioration of lithium secondary battery >
The method of diagnosing the cause of deterioration of a lithium secondary battery of the present invention includes: (A) manufacturing a lithium secondary battery including a cathode and an anode, the cathode including a layered cathode active material; (B) obtaining a first pattern showing a change in a c-axis d-spacing value of the layered positive electrode active material according to a number of moles of lithium ions deintercalated from the layered positive electrode active material during charging, from XRD data obtained during first charging of the lithium secondary battery; (C) obtaining a second pattern showing a change in a c-axis d-spacing value of the layered positive electrode active material according to a number of moles of lithium ions deintercalated from the layered positive electrode active material during charging, from XRD data obtained during second charging of the lithium secondary battery; and (D) classifying the cause of deterioration of the lithium secondary battery by comparing the first pattern and the second pattern.
Conventionally, the cause of deterioration of a battery cannot be determined using only the charge potential distribution of a full battery, and the cause of deterioration of a battery can be determined only by disassembling the full battery, reassembling the positive and negative electrodes obtained therefrom into individual half batteries, and verifying the cause by analyzing the half batteries. Fig. 1 shows a graph illustrating charge potential distributions of a full cell and a positive-electrode half cell and a negative-electrode half cell manufactured using a positive electrode and a negative electrode obtained by disassembling the full cell, which are obtained to diagnose the cause of deterioration of a lithium secondary battery by a conventional method. The full cell of fig. 1(a) and the full cell of fig. 1(b) are different full cells.
Referring to the full-battery charging potential distribution shown in fig. 1(a) and 1(b), it can be seen from the fact that the charging capacity (charging capacity of a deteriorated battery) indicated by a solid line is decreased as compared with the charging capacity (initial charging capacity of a battery) indicated by a dotted line, deterioration of the battery is progressing. However, the cause of degradation of the battery cannot be determined using only the full-battery charge potential distribution. Therefore, the positive electrode and the negative electrode obtained by disassembling the full cell are assembled into a half cell, and the charge potential distribution of the positive electrode half cell and the negative electrode half cell is obtained.
Referring to the charge distribution of the positive electrode half cell shown in fig. 1(a), it can be seen from the fact that there is no difference between the charge distributions of the positive electrode half cell indicated by the dotted line and the solid line, that the deterioration of the cell is not due to the loss of the positive electrode capacitance. Therefore, in order to determine the cause of degradation of the battery, in fig. 1(a), the full-battery charging potential distribution indicated by the solid line and the negative-electrode half-battery charging potential distribution indicated by the solid line are horizontally moved in the x-axis direction by the amount of loss of full battery capacity (all the amount of loss of full battery capacity is reflected in the negative-electrode half-battery distribution), and it can be confirmed that the degradation of the battery is due to the loss of available lithium. In addition, it can be seen that an unusable low potential positive electrode region occurs due to deterioration that occurs as a result of reversible lithium ion loss by a side reaction that consumes lithium ions.
Referring to the positive electrode half cell charge distribution shown in fig. 1(b), from the fact that the positive electrode half cell distribution indicated by the solid line does not overlap with the positive electrode half cell distribution indicated by the broken line, it can be confirmed that the deterioration of the battery is caused by the loss of the positive electrode capacity.
As described above, conventionally, in order to diagnose a specific cause of battery deterioration, it is necessary to disassemble a battery, reassemble positive and negative electrodes separated therefrom into a half-cell, and then analyze it to verify the cause, and therefore, there are problems in that diagnosis of battery deterioration is time-consuming and expensive, and the disassembled battery cannot be reused.
The present invention relates to a method for classifying causes of deterioration of a lithium secondary battery without disassembling a full battery by determining a c-axis d-spacing value of a layered positive electrode active material based on XRD data. The method of diagnosing the cause of deterioration of a lithium secondary battery of the present invention is a nondestructive diagnosis method, and therefore, as long as the lithium secondary battery is not completely deteriorated, it is advantageous in that the secondary battery can be reused after the cause of deterioration of the lithium secondary battery is determined.
Hereinafter, each step of the present invention will be described in more detail.
Step (A)
First, the present invention includes a step (a) of manufacturing a lithium secondary battery including: a positive electrode including a layered positive electrode active material; and a negative electrode.
Specifically, the step (a) may be a step of manufacturing a lithium secondary battery including: a positive electrode including a layered positive electrode active material; a negative electrode opposite to the positive electrode; a separator disposed between the positive electrode and the negative electrode; and an electrolyte.
The positive electrode of the present invention can be manufactured by applying a composition for forming a positive electrode (including a layered positive electrode active material, a binder, a conductive material, a solvent, and the like) onto a positive electrode collector to form a positive electrode active material layer. In addition, the positive electrode-forming composition may optionally further include a dispersant, if necessary.
In the present invention, in order to realize a secondary battery having a high energy density, the layered cathode active material may be a lithium transition metal oxide containing 60 mol% or more of Ni with respect to the total number of moles of transition metals other than lithium. Specifically, according to the present invention, the layered cathode active material may be represented by the following chemical formula 1.
[ chemical formula 1]
Li1+aNixCoyMzO2
In chemical formula 1 above, 0. ltoreq. a.ltoreq.0.3, 0.6. ltoreq. x.ltoreq.1.0, 0. ltoreq. y.ltoreq.0.2, 0. ltoreq. z.ltoreq.0.2, and x + y + z ═ 1, and M may be one or more selected from Mn and Al.
In chemical formula 1 above, M may be an element substituted at a transition metal site in the oxide represented by chemical formula 1.
In the oxide represented by the above chemical formula 1, 1+ a represents a molar ratio of lithium, and may be 0. ltoreq. a.ltoreq.0.3, preferably 0. ltoreq. a.ltoreq.0.2.
In the oxide represented by the above chemical formula 1, x represents a molar ratio of Ni, and may be 0.6. ltoreq. x.ltoreq.1.0, preferably 0.8. ltoreq. x.ltoreq.1.0.
In the oxide represented by the above chemical formula 1, y represents a molar ratio of Co, and may be 0. ltoreq. y.ltoreq.0.2, preferably 0. ltoreq. y.ltoreq.0.15.
In the oxide represented by the above chemical formula 1, z represents a molar ratio of M, and may be 0. ltoreq. z.ltoreq.0.2, preferably 0. ltoreq. z.ltoreq.0.15.
When the layered positive electrode active material contains 60 mol% or more, specifically 80 mol% or more of Ni with respect to the total number of moles of transition metals other than lithium, that is, particularly, when the layered positive electrode active material has a high Ni content, the phase of the positive electrode active material may be changed due to deintercalation of lithium ions present in the positive electrode active material at a high potential. That is, the structural stability of the cathode active material may be reduced, which may cause deterioration of the cathode and, ultimately, deterioration (performance deterioration) of the lithium secondary battery. The method of diagnosing the cause of deterioration of a lithium secondary battery of the present invention is characterized in that it is capable of diagnosing the cause of deterioration of a lithium secondary battery without disassembling the battery.
In the positive electrode, the positive electrode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has conductivity, and for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel whose surface is treated with carbon, nickel, titanium, silver, or the like may be used. In addition, the positive electrode collector may generally have a thickness of 3 to 500 μm, and the collector may have fine irregularities formed on the surface thereof to increase adhesion of the positive electrode active material. The positive electrode collector may be used in any shape, for example, a film, a sheet, a foil, a mesh, a porous material, a foam, a nonwoven fabric, or the like.
The binder is used to improve adhesion between the positive electrode active material particles and between the positive electrode active material and the positive electrode current collector. Specific examples thereof include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber, or various copolymers thereof, which may be used alone or in combination of two or more thereof.
The conductive material is used to impart conductivity to the electrode, and may be used without particular limitation so long as it does not cause chemical changes in the battery to be manufactured and has electronic conductivity. Specific examples thereof include: graphite, such as natural graphite or artificial graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black or thermal black; carbon-based materials, such as carbon fibers; metal powder or metal fiber of copper, nickel, aluminum, silver, or the like; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; and conductive polymers such as polyphenylene derivatives, which may be used alone or in combination of two or more thereof.
The dispersant may be used without particular limitation as long as it is a material used as a positive electrode dispersant, and for example, an aqueous dispersant or an organic dispersant may be selectively used as needed. Preferably, examples of the dispersant include cellulose-based compounds, polyalkylene oxides, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl acetal, polyvinyl ether, polyvinyl sulfonic acid, polyvinyl chloride (PVC), PVDF, chitosan, starch, amylose, polyacrylamide, poly (N-isopropylacrylamide), poly (N, N-dimethylacrylamide), polyethyleneimine, polyoxyethylene, poly (2-methoxyethoxyethylene), poly (acrylamide-co-diallyldimethylammonium chloride), acrylonitrile/butadiene/styrene (ABS) polymer, acrylonitrile/styrene/acrylate (ASA) polymer, a combination of ASA polymer and propylene carbonate, styrene/acrylonitrile (SAN) copolymer, methyl methacrylate/acrylonitrile/butadiene/styrene (MABS) polymer, methyl methacrylate/styrene (ABS) copolymer, polyvinyl chloride, SBR, nitrile rubber, fluororubber and the like, which may be used alone or in combination of two or more thereof. Hydrogenated nitrile rubber (H-NBR) may be used. When the positive electrode active material layer additionally includes a dispersant, the dispersibility of the components of the positive electrode active material layer, particularly, the conductive material may be increased, but the present invention is not limited thereto.
The solvent may be a solvent commonly used in the art, for example, Dimethylsulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, water, etc., which may be used alone or in combination of two or more thereof. The amount of the solvent used is sufficient if the solvent is capable of dissolving or dispersing the positive electrode active material, the conductive material, and the binder, and a viscosity capable of exhibiting excellent thickness uniformity is achieved when the slurry is coated to manufacture the positive electrode at a later point in time, in consideration of the coating thickness and production yield of the slurry.
The anode of the present invention can be manufactured by coating a composition for anode formation containing an anode active material, a binder, a conductive material, a solvent, and the like on an anode current collector to form an anode active material layer. In addition, the negative electrode-forming composition may optionally further contain a dispersant, if necessary.
As the negative electrode active material, a compound capable of reversibly intercalating and deintercalating lithium may be used. Preferably, the anode includes a silicon-based anode active material exhibiting high capacity characteristics. In addition, the anode active material may additionally include a carbon-based anode active material as well as a silicon-based anode active material. For example, when the anode active material includes a silicon-based anode active material and a carbon-based anode active material, high capacity characteristics are exhibited, while irreversible capacity is reduced as compared to when only the silicon-based anode active material is included.
In the anode, the anode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has conductivity, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel whose surface is treated with carbon, nickel, titanium, silver, or the like may be used. Specifically, a transition metal (e.g., copper or nickel) capable of effectively absorbing carbon may be used as the current collector. In addition, the anode current collector may generally have a thickness of 3 to 500 μm, and the current collector may have fine irregularities formed in a surface thereof to increase adhesion of the anode active material. The anode current collector may be used in any shape, for example, a film, a sheet, a foil, a mesh, a porous material, a foam, a nonwoven fabric, or the like.
The conductive material, binder, solvent, or dispersant contained in the composition for forming a negative electrode may be used without particular limitation as long as it can be generally used in the composition for forming an electrode. For example, the conductive material, the binder, the solvent, or the dispersant described in the above-described composition for forming a positive electrode can be used.
Meanwhile, in the lithium secondary battery in which a separator is used to separate the anode and the cathode and provide a passage for lithium ion migration, any separator commonly used in the lithium secondary battery may be used without particular limitation, and in particular, a separator that exhibits low resistance to migration of electrolyte ions and has excellent electrolyte impregnation ability is preferable. Specifically, a porous polymer film, for example, a porous polymer film formed of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene/butene copolymer, an ethylene/hexene copolymer, or an ethylene/methacrylic acid copolymer, or a porous polymer film having a stacked structure of two or more layers may be used. In addition, a general porous nonwoven fabric, for example, a nonwoven fabric made of high-melting glass fiber, polyethylene terephthalate fiber, or the like, may be used. In addition, in order to secure heat resistance or mechanical strength, a coated separator including a ceramic component or a polymer material and optionally having a single layer or a multi-layer structure may be used.
In addition, examples of the electrolyte used in the present invention may include an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel-type polymer electrolyte, an inorganic solid electrolyte, a melt-type inorganic electrolyte, and the like, which can be used to manufacture a lithium secondary battery, but the present invention is not limited thereto.
Specifically, the electrolyte may include an organic solvent and a lithium salt.
As the organic solvent, any organic solvent that can serve as a medium capable of passing ions involved in the cell site reaction may be used without particular limitation. Specifically, as the organic solvent, there can be used: ester solvents such as methyl acetate, ethyl acetate, gamma-butyrolactone or epsilon-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene or fluorobenzene; a carbonate-based solvent such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (MEC), Ethyl Methyl Carbonate (EMC), Ethylene Carbonate (EC), or Propylene Carbonate (PC); alcohol solvents such as ethanol or isopropanol; nitriles such as R-CN and the like (R is a C2-C20 hydrocarbon group having a linear, branched or cyclic structure, which may contain a double-bonded aromatic ring or ether bond), amides such as dimethylformamide; dioxolanes such as 1, 3-dioxolane; sulfolane, and the like. Among them, carbonate-based solvents are preferable, and a combination of cyclic carbonates (e.g., EC, PC, etc.) having high ionic conductivity and high dielectric constant capable of improving charge/discharge performance of a battery and linear carbonate-based compounds (e.g., EMC, DMC, DEC, etc.) having low viscosity is more preferable.
As the lithium salt, any compound capable of providing lithium ions used in a lithium secondary battery may be used without particular limitation. Specifically, LiPF can be used as the lithium salt6、LiClO4、LiAsF6、LiBF4、LiSbF6、LiAlO4、LiAlCl4、LiCF3SO3、LiC4F9SO3、LiN(C2F5SO3)2、LiN(C2F5SO2)2、LiN(CF3SO2)2、LiCl、LiI、LiB(C2O4)2And the like.
In the electrolyte, in addition to the above-mentioned electrolyte components, one or more additives such as halogenated alkylene carbonate-based compounds (e.g., ethylene difluorocarbonate), pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, N-ethylene glycol dimethyl ether, hexamethylphosphoric triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinone, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salts, pyrrole, 2-methoxyethanol, aluminum trichloride, and the like may be contained to improve the life characteristics of the battery, suppress the decrease in the battery capacity, improve the discharge capacity of the battery, and the like.
Steps (B) and (C)
The present invention comprises step (B): from XRD data obtained during the first charge of the lithium secondary battery, a first pattern showing the change in the c-axis d-spacing value of the layered cathode active material during charge as a function of the number of moles of lithium ions deintercalated from the layered cathode active material was obtained.
Further, the present invention comprises step (C): from the XRD data obtained during the second charge of the lithium secondary battery, a second pattern showing the change in the c-axis d-spacing value of the layered cathode active material during charge as a function of the number of moles of lithium ions deintercalated from the layered cathode active material was obtained.
In the present invention, the first charge means initial charge. That is, the first charge refers to initial charge performed immediately after the lithium secondary battery is manufactured.
In the present invention, the second charging may be charging performed after discharging the lithium secondary battery subjected to the first charging and then repeating charging and discharging the lithium secondary battery for one or more cycles. In addition, the second charge may be a charge performed after discharging the lithium secondary battery subjected to the first charge and then storing the lithium secondary battery at a temperature of-20 ℃ to 70 ℃ for a long time.
According to the method of diagnosing the cause of deterioration of a lithium secondary battery of the present invention, the cause of deterioration of the battery can be determined in a simple and non-destructive manner by repeating charging and discharging of the lithium secondary battery within the driving voltage range of the battery, or by storing the lithium secondary battery for a long period of time after the lithium secondary battery is initially charged and discharged. Therefore, even after the cause of deterioration of the lithium secondary battery is diagnosed, the secondary battery can be reused as long as it is not completely deteriorated.
In the present invention, the first charging and the second charging may be performed in a voltage range of 2.5V to 4.2V. Further, one or more repeated charge and discharge cycles may be performed at a voltage range of 2.5V to 4.2V.
In the present invention, XRD data may be obtained using a transmission type XRD analyzer. For example, a transmission XRD analyzer and Ag-Ka made by using Bruker or Malvern Panalytic Ltd
Figure BDA0003534048440000091
The target was measured at a voltage of 50kV and a current of 25mA to obtain XRD data.
In the present invention, the lithium secondary battery is subjected to a first charge (primary charge) or a second charge while irradiating a region where the layered positive electrode active material exists with X-rays, detecting the diffracted X-rays, and determining the degree of deterioration of the secondary battery using the detected diffracted X-rays. The present invention uses a phenomenon that the distance between crystal planes of a layered positive electrode active material changes as lithium ion deintercalation proceeds when a lithium secondary battery is charged.
Specifically, the d-spacing value, i.e., the c-axis distance between crystal planes of the layered cathode active material, may be obtained from XRD data obtained during the first charge or the second charge of the lithium secondary battery, and a graph of the d-spacing value with respect to the number of moles of lithium ions deintercalated during the first charge or the second charge may be plotted, and the degree of degradation of the secondary battery may be determined by comparing a first graph showing the variation of the d-spacing value with the number of moles of lithium ions deintercalated during the first charge with a second graph showing the variation of the d-spacing value with the number of moles of lithium ions deintercalated during the second charge. The specific details related to the determination of the degree of deterioration of the secondary battery by comparing these maps will be described in more detail in step (D).
In the present invention, the d-spacing value may be specifically a d-spacing value of the (003) plane of the layered positive electrode active material. For example, the d-spacing value may represent the long axis length of a hexagonal (space group R3m) unit cell. The unit cell refers to a minimum repeating structure having an arrangement of a transition metal layer/an oxygen layer/a lithium layer in the positive electrode active material.
Step (D)
The present invention includes a step (D) of classifying causes of deterioration of the secondary battery by comparing the first pattern and the second pattern.
In the present invention, the cause of deterioration of the secondary battery may be one or more of loss of usable lithium and loss of positive electrode capacity. That is, step (D) may include determining that the deterioration of the secondary battery is due to a loss of available lithium, a loss of positive electrode capacity, or both of the loss of available lithium and the loss of positive electrode capacity through comparison of the first graph and the second graph, thereby classifying causes of the deterioration.
In the present invention, the step (D) may include classifying the cause of deterioration of the secondary battery as a loss of available lithium when the maximum value of the number of moles of deintercalated lithium ions of the second pattern is less than the maximum value of the number of moles of deintercalated lithium ions of the first pattern, and after horizontally moving the second pattern in the x-axis direction such that the number of moles of deintercalated lithium ions of the second pattern corresponding to the maximum c-axis d-spacing value of the layered cathode active material is the same as the number of moles of deintercalated lithium ions of the first pattern corresponding to the maximum c-axis d-spacing value of the layered cathode active material, when the sum of the maximum number of moles of deintercalated lithium ions of the second pattern and the degree of horizontal movement (x-axis direction) of the second pattern is greater than the maximum number of moles of deintercalated lithium ions of the first pattern, the cause of deterioration of the secondary battery is classified as a loss of positive electrode capacity.
Meanwhile, regarding the occurrence of an unusable low potential positive electrode region due to deterioration caused by reversible lithium ion loss due to a side reaction of consuming lithium ions, it can be seen that the unusable low potential positive electrode region occurs when the number of moles of deintercalated lithium ions corresponding to the maximum c-axis d-spacing value of the layered positive electrode active material of the second pattern is smaller than the number of moles of deintercalated lithium ions corresponding to the maximum c-axis d-spacing value of the layered positive electrode active material of the first pattern.
In the present invention, the step (D) may include quantifying the amount of available lithium loss as a value obtained by subtracting the maximum number of moles of deintercalated lithium ions of the second pattern from the maximum number of moles of deintercalated lithium ions of the first pattern. The loss amount of available lithium is a value obtained by subtracting the maximum number of moles of deintercalated lithium ions of the second pattern from the maximum number of moles of deintercalated lithium ions of the first pattern. The maximum number of moles of deintercalated lithium ions of the first pattern or the second pattern is the maximum amount of lithium available during the first charge or the second charge. That is, the loss amount of available lithium determined by comparing the first graph and the second graph is a value obtained by subtracting the maximum amount of available lithium during the second charge from the maximum amount of available lithium during the first charge, and from this value, the degree of degradation of the battery can be determined.
In addition, the step (D) may include quantifying the equilibrium shift of the positive and negative electrodes based on the degree to which the second pattern is horizontally moved (in the x-axis direction such that the number of moles of deintercalated lithium ions of the second pattern corresponding to the maximum c-axis D-spacing value of the layered positive electrode active material is the same as the number of moles of deintercalated lithium ions of the first pattern corresponding to the maximum c-axis D-spacing value of the layered positive electrode active material). In the present specification, the above-mentioned equilibrium shift means deterioration due to loss of reversible lithium ions by a side reaction of consuming lithium ions. The equilibrium shift refers to the degree to which the second pattern moves horizontally, and is obtained by subtracting the number of moles of deintercalated lithium ions of the second pattern corresponding to the maximum d-spacing value from the number of moles of deintercalated lithium ions of the first pattern corresponding to the maximum d-spacing value. As can be seen from the shift in the equilibrium, as the working range of the positive electrode is changed, overcharge (over-delithiation) occurs.
Additionally, step (D) may include quantifying an amount of loss of positive electrode capacity. The loss amount of the positive electrode capacity may be quantified as a value obtained by subtracting the maximum mole number of the deintercalated lithium ions of the first pattern from the sum of the maximum mole number of the deintercalated lithium ions of the second pattern and the degree of horizontal movement (in the x-axis direction) of the second pattern.
That is, according to the present invention, the cause of deterioration of the secondary battery can be quantified.
In the method of diagnosing the cause of deterioration of a lithium secondary battery of the present invention, when the loss rate of available lithium according to the following equation 1 is 14% or more, it may be determined that the deterioration of the lithium secondary battery is due to the loss of available lithium.
[ equation 1]
Loss ratio of available lithium (loss amount of available lithium)/(maximum number of moles of deintercalated lithium ions of first pattern) × 100
End of life (EOL) is defined as the life of a lithium secondary battery, and generally refers to a point of time when the battery capacity reaches 80% of the initial capacity of the battery. That is, when the capacity of the lithium secondary battery is reduced by 20% from the initial capacity, it can be considered that the lithium secondary battery has been deteriorated.
Although the deterioration of the secondary battery may be due to loss of available lithium due to side reactions, deterioration of the positive electrode due to reduction of the positive electrode reaction region, deterioration of the negative electrode due to reduction of the negative electrode reaction region, and the like, the inventors of the present invention have obtained the c-axis d-spacing value of the layered positive electrode active material based on XRD data without disassembling the full battery, thereby confirming that about 14% of the capacity reduction of 20% is due to loss of available lithium in the case of deterioration of the secondary battery.
Therefore, according to the method of diagnosing the cause of deterioration of a lithium secondary battery of the present invention, even without disassembling the secondary battery after charging and discharging the battery, a decrease in the amount of available lithium, a decrease in the capacity of the positive electrode, and the like can be confirmed, and therefore, the cause of deterioration of the lithium secondary battery can be determined in a simple and nondestructive manner. Therefore, the lithium secondary battery can be repeatedly used even after the cause of deterioration of the secondary battery is diagnosed.
Examples of the invention
Hereinafter, the present invention will be described in detail by way of exemplary embodiments. However, the exemplary embodiments of the present invention may be implemented in various modified forms, and the scope of the present invention should not be construed as being limited to the exemplary embodiments described below. The exemplary embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.
Examples
Example 1
LiNi as a positive electrode active material0.8Co0.1Mn0.1O2The carbon black conductive material, the dispersant, and the PVDF binder were mixed in a NMP solvent at a weight ratio of 97.5:1:0.15:1.35, thereby obtaining a composition for forming a positive electrode. The positive electrode-forming composition was coated on an aluminum foil, dried and rolled, thereby obtaining a positive electrode.
Meanwhile, a 90:10 (weight/weight) mixture of graphite and SiO was used as a negative electrode active material, and the negative electrode active material, carbon black, carbon nanotube conductive material, and binder were mixed at a weight ratio of 96:0.5:0.1:3.4, and then added to a solvent, thereby obtaining a composition for forming a negative electrode. The negative electrode-forming composition was coated on a 6 μm-thick copper current collector, dried and rolled, thereby obtaining a negative electrode.
The positive and negative electrodes manufactured as described above and a Safety Reinforced Separator (SRS) were stacked together to form an electrode assembly. The electrode assembly was placed in a battery case, and an electrolyte prepared by dissolving an electrolyte salt in a mixed solvent (volume ratio of 25:5:70) containing EC, PC, and EMC was injected into the battery case, thereby obtaining a lithium secondary battery.
The lithium secondary battery manufactured as described above was mounted on a transmission XRD analyzer (manufactured by Bruker), and second charging was performed to 4.2V at a 0.025C cutoff under X-ray irradiation at a constant current of 0.05C, thereby obtaining XRD data of a (003) plane corresponding to the interlayer spacing of the positive electrode active material. (use of Ag-K.alpha.
Figure BDA0003534048440000121
The target was measured at a voltage of 50kV and a current of 25 mA. )
The d-spacing value of the (003) plane of the positive electrode active material was determined from the above XRD data obtained from the (003) plane, and thus a first pattern showing the change in the c-axis d-spacing value of the layered positive electrode active material with the number of moles of lithium ions deintercalated from the layered positive electrode active material during initial charging was obtained. The first graph is shown in fig. 2 (a).
Subsequently, the initially charged lithium secondary battery was stored at 60 ℃ for six weeks. After the lithium secondary battery was stored at 60 ℃ for six weeks, the lithium secondary battery was mounted on a transmission XRD analyzer (manufactured by Bruker), and subjected to secondary charging to 4.2V at a cutoff of 0.025C under X-ray irradiation at a constant current of 0.05C, thereby obtaining XRD data of (003) plane corresponding to the interlayer spacing of the cathode active material. (use of Ag-K.alpha.
Figure BDA0003534048440000122
The target was measured at a voltage of 50kV and a current of 25 mA. )
The d-spacing value of the (003) plane of the positive electrode active material was determined from the above XRD data obtained from the (003) plane, and thus a second pattern showing the change in the c-axis d-spacing value of the layered positive electrode active material with the number of moles of lithium ions deintercalated from the layered positive electrode active material during the second charge was obtained. The second graph is shown in fig. 2 (a).
The cause of deterioration of the lithium secondary battery of example 1 was determined by comparing the first graph and the second graph of fig. 2 (a).
Specifically, from fig. 2(a), the difference (0.124 mol) between the maximum number of moles of deintercalated lithium ions (0.856 mol) in the first pattern and the maximum number of moles of deintercalated lithium ions (0.732 mol) in the second pattern, it can be seen that the loss of available lithium is a cause of deterioration of the lithium secondary battery, and the loss amount of available lithium is 0.124 mol. In addition, it can be seen that the loss rate of usable lithium was 14.5%.
Meanwhile, fig. 2(b) shows a graph obtained by horizontally shifting the second pattern of fig. 2(a) by about 0.15 in the x-axis direction, which makes the number of moles of deintercalated lithium ions of the second pattern corresponding to the maximum c-axis d-spacing value of the layered cathode active material the same as the number of moles of deintercalated lithium ions of the first pattern of fig. 2(a) corresponding to the maximum c-axis d-spacing value of the layered cathode active material. As can be seen from the fact that the degree of horizontal shift of the second pattern (i.e., the equilibrium shift) is greater than 0, overcharge (over-delithiation) occurs when the operating range of the positive electrode of the secondary battery of example 1 is changed.
In addition, according to the fact that the maximum number of moles of deintercalated lithium ions (0.882 mol ═ 0.732 mol +0.15 mol (equilibrium shift)) of the second pattern of fig. 2(b) is larger than the maximum number of moles of deintercalated lithium ions (0.856 mol) of the first pattern of fig. 2(b), it can be seen that the deterioration is caused not only by the loss of the above-mentioned available lithium but also by the loss of the positive electrode capacity.
Therefore, it can be seen that when the method of diagnosing the cause of deterioration of a lithium secondary battery of the present invention is used, the cause of deterioration of the lithium secondary battery can be classified and quantified in a simple and lossless manner.

Claims (12)

1. A method of diagnosing a cause of deterioration of a lithium secondary battery, the method comprising:
(A) manufacturing a lithium secondary battery including a cathode and an anode, the cathode including a layered cathode active material;
(B) obtaining a first graph showing a change in a c-axis d-spacing value of the layered positive electrode active material according to a number of moles of lithium ions deintercalated from the layered positive electrode active material during charging, from X-ray diffraction data obtained during first charging of the lithium secondary battery;
(C) obtaining a second graph showing a change in a c-axis d-spacing value of the layered positive electrode active material according to a number of moles of lithium ions deintercalated from the layered positive electrode active material during charging, from X-ray diffraction data obtained during second charging of the lithium secondary battery; and
(D) the causes of deterioration of the lithium secondary battery are classified by comparing the first pattern and the second pattern.
2. The method according to claim 1, wherein the cause of deterioration of the lithium secondary battery is one or more selected from the group consisting of a loss of available lithium and a loss of positive electrode capacity.
3. The method of claim 1, wherein the step (D) comprises:
classifying a cause of deterioration of the secondary battery as a loss of available lithium when the maximum value of the number of moles of deintercalated lithium ions of the second pattern is smaller than the maximum value of the number of moles of deintercalated lithium ions of the first pattern; and
after horizontally moving the second pattern in the x-axis direction such that the number of moles of deintercalated lithium ions of the second pattern corresponding to the maximum c-axis d-spacing value of the layered positive electrode active material is the same as the number of moles of deintercalated lithium ions of the first pattern corresponding to the maximum c-axis d-spacing value of the layered positive electrode active material, when the sum of the maximum number of moles of deintercalated lithium ions of the second pattern and the degree of horizontal movement of the second pattern is greater than the maximum number of moles of deintercalated lithium ions of the first pattern, classifying the cause of degradation of the secondary battery as a loss of positive electrode capacity.
4. The method of claim 3, wherein the step (D) comprises quantifying the amount of available lithium loss as a value obtained by subtracting the maximum moles of de-intercalated lithium ions of the second pattern from the maximum moles of de-intercalated lithium ions of the first pattern.
5. The method of claim 3, wherein the step (D) comprises quantifying the amount of loss of positive electrode capacity as a value obtained by subtracting the maximum number of moles of deintercalated lithium ions of the first pattern from the sum of the maximum number of moles of deintercalated lithium ions of the second pattern and the degree of horizontal movement of the second pattern.
6. The method of claim 4, wherein when the loss rate of available lithium is 14% or more according to the following equation 1, it is determined that the deterioration of the lithium secondary battery is due to the loss of available lithium:
[ equation 1]
The loss rate of available lithium (loss amount of available lithium)/(maximum number of moles of deintercalated lithium ions of the first pattern) × 100.
7. The method according to claim 1, wherein the layered positive electrode active material is a lithium transition metal oxide containing 60 mol% or more of nickel with respect to the total number of moles of transition metals other than lithium.
8. The method of claim 1, wherein the layered positive active material is represented by the following chemical formula 1:
[ chemical formula 1]
Li1+aNixCoyMzO2，
Wherein, in chemical formula 1,
a is more than or equal to 0 and less than or equal to 0.3, x is more than or equal to 0.6 and less than or equal to 1.0, y is more than or equal to 0 and less than or equal to 0.2, z is more than or equal to 0 and less than or equal to 0.2, x + y + z is 1, and M is one or more selected from manganese and aluminum.
9. The method of claim 1, wherein the second charging is:
charging after discharging the lithium secondary battery subjected to the first charging and then repeating charging and discharging the lithium secondary battery for one or more cycles; or
Charging after discharging the lithium secondary battery subjected to the first charging and then storing the lithium secondary battery at a temperature of-20 ℃ to 70 ℃ for a long time.
10. The method of claim 1, wherein the first and second charging are performed at a voltage ranging from 2.5V to 4.2V.
11. The method of claim 1, wherein the X-ray diffraction data is obtained using a transmissive X-ray diffraction analyzer.
12. The method of claim 1, wherein the d-spacing value is a d-spacing value of a (003) plane of the layered positive electrode active material.
CN202180005251.7A 2020-05-27 2021-04-28 Diagnosis of cause of deterioration of lithium secondary battery Active CN114375392B (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
KR1020200063393A KR20210146521A (en) 2020-05-27 2020-05-27 Diagnostic method of cause of degradation of lithium secondary battery
KR10-2020-0063393 2020-05-27
PCT/KR2021/005365 WO2021241899A1 (en) 2020-05-27 2021-04-28 Method for diagnosing cause of degradation of lithium secondary battery

Publications (2)

Publication Number Publication Date
CN114375392A true CN114375392A (en) 2022-04-19
CN114375392B CN114375392B (en) 2023-11-03

Family

ID=78744908

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202180005251.7A Active CN114375392B (en) 2020-05-27 2021-04-28 Diagnosis of cause of deterioration of lithium secondary battery

Country Status (9)

Country Link
US (1) US12013356B2 (en)
EP (1) EP4009041B1 (en)
JP (1) JP7292665B2 (en)
KR (1) KR20210146521A (en)
CN (1) CN114375392B (en)
ES (1) ES2945832T3 (en)
HU (1) HUE062023T2 (en)
PL (1) PL4009041T3 (en)
WO (1) WO2021241899A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20230166506A (en) * 2022-05-31 2023-12-07 주식회사 엘지에너지솔루션 Apparatus and method for diagnosing battery
KR20240057001A (en) * 2022-10-24 2024-05-02 주식회사 엘지에너지솔루션 Suitability evaluation method for negative electrode active material

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08189907A (en) * 1995-01-09 1996-07-23 Nippon Telegr & Teleph Corp <Ntt> X-ray diffraction apparatus with automatic tester for charging/discharging secondary cell
CN1225518A (en) * 1998-01-30 1999-08-11 佳能株式会社 Lithium secondary battery and method of mfg. lithium secondary battery
KR20070077700A (en) * 2006-01-24 2007-07-27 주식회사 엘지화학 Seconday battery
KR20070106476A (en) * 2007-09-10 2007-11-01 주식회사 소디프신소재 Negative active material for rechargeable lithium battery, and rechargeable lithium battery comprising the same
US20090305140A1 (en) * 2008-06-05 2009-12-10 Industry-University Cooperation Foundation, Hanyang University Electrochemical cell
CN103081212A (en) * 2010-06-07 2013-05-01 丰田自动车株式会社 System and method for determination of deterioration of lithium ion secondary battery
CN103430371A (en) * 2011-03-14 2013-12-04 三菱自动车工业株式会社 Lithium-ion battery capacity recovery method
US20160123906A1 (en) * 2014-10-31 2016-05-05 GM Global Technology Operations LLC Method for Determining the Lithiation of Li-Ion Battery Electrodes
CN110214387A (en) * 2017-07-12 2019-09-06 株式会社Lg化学 Lithium secondary battery and preparation method thereof

Family Cites Families (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5635138A (en) * 1995-01-17 1997-06-03 Bell Communications Research, Inc. Apparatus for in situ x-ray study of electrochemical cells
JP2001110419A (en) 1999-10-13 2001-04-20 Nichia Chem Ind Ltd Evaluation method of safety of overcharge of substance for activating positive electrode for lithium ion secondary battery
JP2007134049A (en) 2001-11-02 2007-05-31 Matsushita Electric Ind Co Ltd Nonaqueous electrolytic liquid secondary battery
JP4228287B2 (en) * 2003-05-26 2009-02-25 トヨタ自動車株式会社 Evaluation method of positive electrode active material for lithium secondary battery
JP2011040281A (en) * 2009-08-11 2011-02-24 Samsung Electronics Co Ltd All-solid secondary battery
US20110039162A1 (en) 2009-08-11 2011-02-17 Samsung Electronics Co., Ltd. All-solid secondary battery and positive electrode used therefor
JP2013131338A (en) * 2011-12-20 2013-07-04 Toyota Motor Corp Deterioration evaluation method of positive electrode active material and lithium ion secondary battery
KR101355973B1 (en) 2012-05-31 2014-01-27 주식회사 엘지화학 Apparatus and method for estimationg state of secondary battery
KR101644684B1 (en) 2014-02-28 2016-08-01 주식회사 엘지화학 Lithium-nikel based cathod active material, preparation method thereof and lithium secondary battery comprising the same
KR101696313B1 (en) 2014-10-24 2017-01-13 주식회사 엘지화학 Method of estimating a SOC-OCV profile in accordance with degradation of the secondary battery
KR101685609B1 (en) 2015-02-04 2016-12-12 울산과학기술원 Positive active material for rechargeable magnesium battery, method for manufacturing the same, and rechargeable magnesium battery including same
JP2017139089A (en) * 2016-02-02 2017-08-10 日本電気株式会社 Secondary battery evaluation method, secondary battery evaluation device, and secondary battery evaluation program
KR102032507B1 (en) 2016-02-25 2019-10-15 주식회사 엘지화학 Pouch case and secondary battery including the same
JP6489529B2 (en) 2016-08-31 2019-03-27 株式会社日産アーク Method and system for estimating state of structural complex
CN108336331B (en) * 2017-01-17 2022-12-20 三星电子株式会社 Electrode active material, lithium secondary battery comprising the same, and method for preparing the same
KR102665139B1 (en) 2017-05-19 2024-05-10 가부시키가이샤 한도오따이 에네루기 켄큐쇼 Positive electrode active material, method for manufacturing positive electrode active material, and secondary battery
JP7081908B2 (en) 2017-08-07 2022-06-07 株式会社半導体エネルギー研究所 Lithium ion secondary battery
KR102259967B1 (en) 2017-12-18 2021-06-02 주식회사 엘지에너지솔루션 Apparatus and method for managing charging of battery
KR102304736B1 (en) * 2018-03-15 2021-09-24 주식회사 엘지에너지솔루션 Negative electrode active material for lithium secondary battery and negative electrode comprising the same
CN108872869B (en) * 2018-06-14 2022-04-12 中山大学 Lithium ion battery degradation classification method based on BP neural network
KR102533811B1 (en) * 2018-12-03 2023-05-19 주식회사 엘지에너지솔루션 Positive electrode active material for secondary battery, method for manufacturing the same, positive electrode for secondary battery and lithium secondary battery comprising the same

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08189907A (en) * 1995-01-09 1996-07-23 Nippon Telegr & Teleph Corp <Ntt> X-ray diffraction apparatus with automatic tester for charging/discharging secondary cell
CN1225518A (en) * 1998-01-30 1999-08-11 佳能株式会社 Lithium secondary battery and method of mfg. lithium secondary battery
KR20070077700A (en) * 2006-01-24 2007-07-27 주식회사 엘지화학 Seconday battery
KR20070106476A (en) * 2007-09-10 2007-11-01 주식회사 소디프신소재 Negative active material for rechargeable lithium battery, and rechargeable lithium battery comprising the same
US20090305140A1 (en) * 2008-06-05 2009-12-10 Industry-University Cooperation Foundation, Hanyang University Electrochemical cell
CN103081212A (en) * 2010-06-07 2013-05-01 丰田自动车株式会社 System and method for determination of deterioration of lithium ion secondary battery
CN103430371A (en) * 2011-03-14 2013-12-04 三菱自动车工业株式会社 Lithium-ion battery capacity recovery method
US20160123906A1 (en) * 2014-10-31 2016-05-05 GM Global Technology Operations LLC Method for Determining the Lithiation of Li-Ion Battery Electrodes
CN110214387A (en) * 2017-07-12 2019-09-06 株式会社Lg化学 Lithium secondary battery and preparation method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
TIMO BARTSCH ET AL.: "Indirect state-of-charge determination of all-solid-state battery cells by X-ray diffraction", 《ROYAL SOCIETY OF CHEMISTRY》, vol. 55, pages 11223 - 11226, XP055891094, DOI: 10.1039/C9CC04453A *

Also Published As

Publication number Publication date
EP4009041A4 (en) 2022-09-07
US12013356B2 (en) 2024-06-18
ES2945832T3 (en) 2023-07-07
US20220393257A1 (en) 2022-12-08
WO2021241899A1 (en) 2021-12-02
HUE062023T2 (en) 2023-09-28
JP7292665B2 (en) 2023-06-19
EP4009041B1 (en) 2023-04-19
CN114375392B (en) 2023-11-03
JP2022549121A (en) 2022-11-24
EP4009041A1 (en) 2022-06-08
KR20210146521A (en) 2021-12-06
PL4009041T3 (en) 2023-07-10

Similar Documents

Publication Publication Date Title
CN111316480B (en) Positive electrode material for lithium secondary battery, positive electrode comprising same, and lithium secondary battery
CN111226330A (en) Positive electrode material for secondary battery and lithium secondary battery comprising same
US11799070B2 (en) Negative electrode active material for lithium secondary battery, method of preparing the same, and negative electrode for lithium secondary battery and lithium secondary battery including the same
US10056611B2 (en) Method for testing cycle life of positive electrode active material for secondary battery
EP4109592A1 (en) Secondary battery
US20220020983A1 (en) Positive Electrode Active Material for Secondary Battery, Preparation Method Thereof, and Positive Electrode for Secondary Battery Including Same
US20220013784A1 (en) Negative electrode and secondary battery including same
KR20190102612A (en) Negative electrode active material for lithium secondary battery, negative electrode for lithium secondry battery and lithium secondary battery comprising the same
US11764349B2 (en) Negative electrode active material for lithium secondary battery and negative electrode for lithium secondary battery including the same
US20220216463A1 (en) Method of Producing Positive Electrode Active Material for Lithium Secondary Battery and Positive Electrode Active Material for Lithium Secondary Battery Produced Thereby
CN114375392B (en) Diagnosis of cause of deterioration of lithium secondary battery
US20220336806A1 (en) Positive Electrode Material for Secondary Battery and Lithium Secondary Battery Comprising Same
CN112204777A (en) Positive electrode active material for lithium secondary battery and lithium secondary battery
US20220294037A1 (en) Method for manufacturing secondary battery
CN112154557B (en) Positive electrode active material for lithium secondary battery and lithium secondary battery
US20220013766A1 (en) Secondary battery
JP7427312B2 (en) Deterioration diagnosis method for electrode active materials for lithium secondary batteries
US20220255150A1 (en) Method of manufacturing secondary battery
CN112204776A (en) Positive electrode active material for lithium secondary battery and lithium secondary battery
JP7460261B2 (en) Secondary battery charging and discharging method
JP2022547282A (en) BATTERY SYSTEM, USAGE THEREOF AND BATTERY PACK INCLUDING THE SAME
CN112154558A (en) Positive electrode active material for lithium secondary battery and lithium secondary battery

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant